Nasopharyngeal Cancers

Understanding the Anatomy

The nasopharynx is the uppermost part of the throat, behind the nasal cavity and above the oropharynx. It’s like a small box about two to three centimeters front to back and about three to four centimeters top to bottom and side to side. You can’t see it by looking inside your mouth or your nose. It is behind and above the soft palate (the soft part of the roof of your mouth that includes the uvula). Actually, when the soft palate lifts up, it forms the floor of the nasopharynx. The nasopharynx is positioned just under and in front of the base of the skull.

NASOPHARYNX

There are many important structures in and around the nasopharynx of which you should be aware.

Choanae: This is the entrance from the nose back into the nasopharyx. There is one on each side from the nose, divided by the nasal septum. If one of these gets blocked by a tumor, you won’t be able to breathe from that side of your nose.

Eustachian tubes: The Eustachian tubes, sometimes called the auditory tubes, lie on each side of the nasopharynx. The Eustachian tube helps equalize pressure inside the ears and helps drain mucous from the middle ear. This is important, because if a nasopharynx tumor blocks the Eustachian tube, you can get mucous build-up in the middle ear, which can in turn lead to difficulty hearing and an ear infection. That is one reason why an ear infection, hearing loss or middle ear fluid on one side that occurs in an adult should be evaluated by a specialist.

Pharyngeal recess (also called the Fossa of Rosenmuller): This is a slit-like space just on the inside of the Eustachian tube opening in the nasopharynx. This is important because the pharyngeal recess is the most common site for NPC to start. When the tumor grows deep, toward the skull base, there may not be any symptoms related to obstruction in the nasopharynx. This is one reason why NPC can sometimes be picked up only once it has invaded nerves in the skull base.

Base of skull: The nasopharynx is located right below and in front of the base of the skull. On the other side of the base of the skull is the brain. NPC, in advanced stages, can destroy the bone at the base of the skull and enter the cranial cavity.

Cranial nerves: These are nerves that perform special functions in the head and neck area, like moving muscles, feeling, hearing, tasting, seeing and speaking. The cranial nerves start in the brain and exit through tiny holes in the base of the skull. NPC can damage some of these nerves, either by extending up into the brain or affecting them as they leave the base of the skull.

Retropharyngeal space: This is a space behind the pharynx, in front of the spine. NPC can spread to lymph nodes in this space.